1. Field of the Invention
The present invention relates to a technique for externally controlling an image capture apparatus, such as a digital video camera, via a digital interface.
2. Description of the Related Art
Communication between a digital video camera (hereinafter referred to as a “DVCR”) and a personal computer (hereinafter referred to as a “PC”) can be established via a digital interface. If the digital interface is compliant with IEEE 1394 (see IEEE Std 1394-1995, IEEE Standard for a High Performance Serial Bus, Institute of Electrical and Electronics Engineers, Inc.; and IEEE Std 1394a-2000, IEEE Standard for a High Performance Serial Bus—Amendment 1), communication is performed on the basis of a command set defined by AV/C Digital Interface Command Set General Specification Version 4.1 (Nov. 19, 2001), or the like. If the digital interface is compliant with USB (see Universal Serial Bus Specification Revision 2.0, Apr. 27, 2000), communication is performed on the basis of a command set defined by Universal Serial Bus Device Class Definition For Video Devices.
The DVCR typically has two transmission modes, camera mode and VTR mode. In the camera mode, video data captured by the DVCR is transmitted in real time to a remote PC via a network. In the VTR mode, video data already captured and recorded on a magnetic tape or memory card loaded in the DVCR is transmitted to a remote PC via a network.
Switching between the camera mode and the VTR mode can be performed by a user operating a mechanical switch provided on the DVCR. However, the DVCR does not allow such switching to be performed in response to a control command transmitted from the PC.
More specifically, the user cannot control switching of the transmission modes of the DVCR by operating the PC. Thus, the user needs to directly operate the mechanical switch of the DVCR for performing such switching. For example, the user may conduct video telephone session by causing the DVCR to capture a video image of the user seated before the PC and to transmit the captured video data in the camera mode. If, during this video telephone session, the user wishes to change the DVCR to the VTR mode to transmit video data of the user's child previously captured and recorded on a magnetic tape, the user must move to the location of the DVCR to operate the mechanical switch thereof. This results in an inconvenience to the user.
Meanwhile, there are user requests for a DVCR having a plurality of types of digital interfaces to enhance convenience.